CN111853208A

CN111853208A - Rotary speed changing box

Info

Publication number: CN111853208A
Application number: CN202010348392.6A
Authority: CN
Inventors: A·J·约翰逊; F·福斯特
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 2019-04-30
Filing date: 2020-04-28
Publication date: 2020-10-30
Also published as: US10851832B2; US20200347879A1

Abstract

A rotary gearbox for a rotary drill rig having a rotary union including a first conduit having a first end defining an outlet, a second conduit having a second end defining an inlet, and a sealing arrangement radially between the first end of the first conduit and the second end of the second conduit. The second conduit is rotatable relative to the first conduit and is arranged coaxially with the first conduit. The first end of the first conduit is received within the second end of the second conduit such that the outlet of the first conduit is downstream of the sealing arrangement.

Description

Rotary speed changing box

Technical Field

The present invention relates generally to rotary gearboxes, and in particular to rotary gearboxes for rotary drilling rigs.

Background

Conventional rotary drills include a rotary gearbox. The rotary gearbox typically includes a gear train mounted within a gearbox housing for transmitting torque from the prime mover to the rotatable tube. The rotary gearbox is movably mounted within the rotary drill such that the pull-down force and the pull-up force are transmitted through the gearbox housing to the rotatable tube. Shear forces during pull-down and pull-up can cause bending and flexing of the transmission housing, which can result in damage to the bolted joints connecting the transmission housing to other parts of the drilling rig, and damage to the gear trains and bearings due to misalignment of the gear trains.

The rotary transmission further includes a swivel assembly for conducting pressurized fluid between the stationary tube and the rotatable tube. The swivel assembly defines a swivel joint (i.e., an interface between the stationary and rotatable tubes) that includes a sealing arrangement. The sealing arrangement for the swivel is a common area of wear and failure of the swivel assembly due to its exposure to abrasive material from the high pressure flow of air, water and debris through the swivel. Thus, the swivel may comprise a complex sealing arrangement to provide an adequate seal.

For example, U.S.6,007,105, entitled "swill Seal Assembly," discloses a rotary Seal Assembly for providing sealed, high pressure fluid communication between relatively rotatable, generally coaxial conduits, wherein dynamic flutter and static misalignment of one conduit relative to the other may occur. A generally tubular irrigation tube is pivotally mounted with respect to one conduit, and a generally tubular seal housing is telescopically received over the irrigation tube and mounted in pivotal hinged relationship with the other conduit. A high pressure, staged rotary seal is supported by the seal housing and maintains the bearing in sealing engagement with the flush tube such that the seal housing and flush tube articulate in unison in response to static misalignment and dynamic bounce, thereby virtually eliminating relative lateral movement between the seal housing and flush tube and minimizing rotary seal crushing damage.

Disclosure of Invention

In one aspect, the present disclosure describes a rotary gearbox for a rotary drill rig having a rotary union including a first conduit having a first end defining an outlet, a second conduit having a second end defining an inlet, and a sealing arrangement radially between the first end of the first conduit and the second end of the second conduit. The second catheter is rotatable relative to the first catheter and is arranged coaxially with the first catheter. The first end of the first conduit is received within the second end of the second conduit such that the outlet of the first conduit is downstream of the sealing arrangement.

In another aspect, the present disclosure describes a rotary gearbox configured to be mounted to a guide of a rotary drill. The rotary transmission includes a plurality of gears and a transmission housing. The transmission housing includes a gear train portion housing a plurality of gears, and a mounting portion defining a mounting surface for mounting the transmission housing to the guide. At least a majority of the mounting surface is spaced from the gear train portion relative to a longitudinal axis of the rotary transmission.

Drawings

Other features and advantages of the present invention will become apparent from the embodiments described using the accompanying drawings.

In the drawings:

FIG. 1 is a schematic illustration of an exemplary embodiment of a rotary gearbox for a rotary drill, wherein the rotary gearbox is attached to a drill guide;

FIG. 2 is a cross-sectional view of the rotary transmission of FIG. 1;

FIG. 3 is an enlarged cross-sectional view of the rotary transmission of FIG. 1 illustrating an exemplary embodiment of a rotary joint of the rotary transmission;

FIG. 4 is a perspective view of the rotary transmission of FIG. 1;

FIG. 5 is an enlarged view of the underside of an exemplary embodiment of the top plate of the rotary transmission of FIG. 1; and

FIG. 6 is an enlarged top end view of an exemplary embodiment of a transmission housing of the rotary transmission of FIG. 1.

Detailed Description

The present disclosure relates to a rotary gearbox 100. According to the present disclosure, the rotary gearbox 100 may be used in a variety of applications, such as, for example, a rotary drill. The rotary transmission 100 may include a rotary joint and features to extend the life of the sealing arrangement for the rotary joint. The rotary transmission 100 may house a gear train and include features that improve the load carrying capacity of the rotary transmission 100 and reduce deflection of the rotary transmission housing portion that houses the gear train. Excessive deflection can lead to gear damage due to misalignment and damage to bolted joints connecting the transmission housing to other parts of the drilling rig.

Fig. 1 is a schematic illustration of an exemplary embodiment of a rotary gearbox 100 attached to one or more first guides 102 and one or more second guides 103 of a rotary drill. The rotary gearbox 100 may be configured to conduct a pressurized fluid, such as a liquid or a gas, between a first conduit 104 and a second conduit 106, which may rotate relative to the first conduit 104 (as shown by arrow a) and is arranged coaxially with the first conduit 104 along a longitudinal axis B. The rotary gearbox 100 includes a sealing arrangement 110 (fig. 3) to seal the rotary joint between the first conduit 104 and the second conduit 106.

The rotary gearbox 100 includes a gearbox housing 112 having a geartrain portion 114 configured to receive a geartrain 116 (fig. 2) of the rotary gearbox 100, and a mounting portion 118 configured to attach the rotary gearbox 100 to the

guides

102, 103 such that the guides can move the rotary gearbox up (pull up) and down (pull down) as indicated by arrow D. In the illustrated embodiment, the mounting portion 118 is offset from the gear train portion 114 along the longitudinal axis B to at least partially isolate the gear train portion 114 from shear and bending forces transmitted to the gearbox housing 112 via the

guides

102, 103 during operation of the rotary drill. In some embodiments, the mounting portion 118 may be axially spaced from the gear train portion 114 (i.e., vertically spaced in the orientation shown in fig. 1). However, in other embodiments, a majority of the mounting portion 118 is spaced apart from the gear train portion 114 such that a portion of the mounting portion 118 may axially overlap a portion of the gear train portion 114.

The mounting portion 118 may be configured to attach to the

guides

102, 103 in a variety of ways, such as, for example, a bolted joint. Any suitable connection configuration may be used. In the illustrated embodiment, the mounting portion 118 includes one or more first mounting surfaces 122 and one or more second mounting surfaces 124. In the illustrated embodiment, the one or more first mounting surfaces 122 and the one or more second mounting surfaces 124 are below (along the longitudinal axis B) and below (radially relative to the longitudinal axis B) the gear train portion 112. One or more first spacers 120 may extend between the one or more first guides 102 and the one or more first mounting surfaces 122 on the mounting portion 118, and one or more second spacers 123 may extend between the one or more second guides 103 and the one or more second mounting surfaces 124 on the mounting portion 118. The one or more first and

second spacers

120, 123 are configured to facilitate securely bolting the one or more first and

second guides

102, 103 to the transmission housing 112. However, in other embodiments, one or more of the first guide 102 and the second guide 103 may be attached to the mounting portion 118 without using spacers.

Referring to FIG. 2, the rotating transmission housing 112 may be constructed in a variety of ways. In the illustrated embodiment, the gear train portion 114 of the transmission housing 112 is positioned above the mounting portion 118. Gear train portion 114 includes a planar tip 130 and forms a cavity 132 that is open at tip 130. The cavity 132 is configured to receive the gear train 116 of the rotary transmission 100.

A top plate 136 may be mounted to the top end 130 of the gear train portion 114 to cover the cavity 132. Top plate 136 may be attached to top end 130 in any suitable manner. In the illustrated embodiment, the top plate 136 is bolted to the top end 130 to form a top bolted joint.

The gear train 116 may be constructed in various ways. Any gear train configuration that allows for the transfer of rotational movement to the rotatable second conduit 106 may be used. For example, any suitable number of gears, gear types, and gear arrangements may be used. In the illustrated embodiment, the gear train 116 includes a gear train having a sun gear 140 mounted within the gear train portion 114 so as to be rotatable about the longitudinal axis B. The drive train 116 may further include a pair of external gears 142 rotatably mounted within the gear train portion 114. A pair of outer gears 142 are disposed on opposite sides of the sun gear 140. In the illustrated embodiment, each of the outer gears 142 is a compound gear having a lower gear 144 arranged to mate with the sun gear 140 and a larger upper gear 146. The drive train 116 includes a pair of input gears (not shown). Each of the pair of input gears 148 is arranged to mate with a corresponding one of the upper gears 146 of the pair of outer gears 142. A pair of input gears (not shown) is configured to transmit electric power from a prime mover (not shown), such as a hydraulic motor, for example, to the outer gear 142.

Gear train 116 is configured to transfer rotational motion from a prime mover (not shown) to rotatable second conduit 106. The gear train 116 may engage the second conduit 106 in a variety of ways. In the illustrated embodiment, the second conduit 106 extends through a central opening 150 in the sun gear 140 along the longitudinal axis B. The sun gear 140 is connected to the second conduit 106 such that the sun gear 140 and the second conduit 106 rotate together. The sun gear 140 may be connected to the second conduit 106 for rotation therewith by any suitable means, such as, for example, welding, press fitting, splined connection, or other suitable connection.

In the illustrated embodiment, the second conduit 106 extends through the gear train portion 114 and through the mounting portion 118 of the rotary transmission housing 112. The second conduit 106 includes a first end 152, a second end 154 opposite the first end 152, and a central passage 156 extending through the second conduit 106 from the first end 152 to the second end 154. The first end 152 defines an inlet for fluid to flow through the second conduit 106 in the flow direction shown by arrow C in fig. 2. The second conduit 106 is positioned within the transmission housing 112 such that the first end 152 extends from the gear train portion 114 of the transmission housing 112 and the second end 154 extends from the mounting portion 118 of the transmission housing 112.

The second conduit 106 may be rotatably mounted in any suitable manner within the rotary gearbox housing 112. In the illustrated embodiment, the second conduit 106 is rotatably mounted within the rotating gearbox housing 112 by a plurality of roller bearings. The plurality of roller bearings may be configured in a variety of ways, for example, the number of roller bearings, the location of the roller bearings, and the type of roller bearings may vary in different embodiments.

In the illustrated embodiment, the first roller bearing 160 is disposed between the second conduit 106 and the transmission housing 112 and/or the top plate 136 at or near the first end 152. In the illustrated embodiment, the first roller bearing 160 is a straight roller bearing. However, in other embodiments, the first roller bearing 160 may be configured in other ways, such as, for example, a tapered roller bearing.

The second roller bearing 162 is disposed between the second conduit 106 and the gearbox housing 112 and is positioned at or towards the middle of the gearbox housing 112 relative to the longitudinal axis B. In the illustrated embodiment, the second roller bearing 162 is disposed at or near the transition from the gear train portion 114 to the mounting portion 118, and the sun gear 140 engages the second conduit 106 at a location along the longitudinal axis B between the first roller bearing 160 and the second roller bearing 162.

The second roller bearing 162 is a tapered roller bearing that is arranged to taper outwardly in a downward direction (i.e., a direction from the first end 152 toward the second end 154 of the second conduit 106). Thus, the second roller bearing 162 is considered a pull-down bearing because the outward taper positions the second roller bearing 162 to be exposed to a greater amount of pull-down force of the drill than other bearings.

A third roller bearing 164 is disposed between the second conduit 106 and the transmission housing 112 and is positioned at or near the second end 154 of the second conduit 106. The third roller bearing 164 is a tapered roller bearing arranged to taper inwardly in a downward direction (i.e., a direction from the first end 152 toward the second end 154 of the second conduit 106). Thus, the third roller bearing 164 is considered a pull-up bearing because the inward taper positions the third roller bearing 164 to be exposed to a greater amount of pull-up force of the drill than other bearings. In other embodiments, the second and

third roller bearings

162, 164 may not be tapered. Since the drill rig's pull-down force is greater than the pull-up force, and is typically applied for a longer duration than the pull-up force, it is advantageous to have the second roller bearing 162 at or near the longitudinal middle of the transmission housing 112 (where more of the housing structure surrounds and supports the second roller bearing 162).

Referring to fig. 3, the interface between the first conduit 104 and the second conduit 106 forms a swivel. The rotary joint may be constructed in various ways. The swivel may include a variety of features configured to seal and maintain a seal between the first conduit 104 and the second conduit 106. In the illustrated embodiment, the rotary gearbox 100 includes a sealing arrangement 110 and a guide feature that causes flow to exit the first conduit 104 and enter the second conduit 106 downstream of the sealing arrangement 110.

In the illustrated embodiment, the first conduit 104 includes a first end 170, a second end 172 opposite the first end 170, and a passageway 174 extending through the first conduit 104 from the first end 170 to the second end 172. Second end 172 defines an outlet for fluid to flow through first conduit 104 in a flow direction indicated by arrow C. The first conduit 104 is configured to be mounted to the rotating transmission housing 112 (fig. 2) such that the second end 172 of the first conduit 104 is received within the first end 152 of the second conduit 106 and the passageway 174 of the first conduit 104 is coaxial with the passageway 156 of the second conduit 106.

In the illustrated embodiment, the first conduit 104 is mounted to the rotary gearbox housing 112 via the mounting ring 176 and the top plate 136. Specifically, the first conduit 104 is mounted to the mounting ring 176, and the mounting ring 176 is mounted to the top plate 136. The first conduit 104, the mounting ring 176, and the top plate 136 may be mounted to one another in any suitable manner.

In the embodiment shown, the first conduit 104 is generally cylindrical and includes an attachment portion. The attachment portion may be configured in a variety of ways to attach the first conduit 104 to the transmission housing 112. In the illustrated embodiment, the attachment portion is an outer annular flange 180 configured to facilitate bolting of the first conduit 104 to the mounting ring 176. In the illustrated embodiment, the first conduit 104 is bolted to the mounting ring 176, and the mounting ring 176 is bolted to the top plate 136. However, in other embodiments, the first conduit 104 may be mounted directly to the transmission housing 112 or the top plate 136. The second end 172 of the first conduit 104 is configured to be received within the first end 152 of the second conduit 106 and has an outer diameter D1.

In the illustrated embodiment, the first end 152 of the second conduit 106 includes a counterbore defined by an outwardly facing shoulder 184 and a cylindrical inner side surface 186. The diameter of the cylindrical inner side surface 186 is slightly larger than the outer diameter D1 of the second end 172 of the first conduit 104. When the second end 172 is received within the counterbore of the first end 152 of the second conduit 106, the second end 172 abuts or is adjacent the shoulder 184. Thus, the second end 172 forms a guide feature for the rotary joint. In the illustrated embodiment, the first catheter 104 is a single piece with the guide feature and the attachment portion is integrally formed. However, in other embodiments, the first catheter 104 may be formed from multiple components such that, for example, the guide feature and the attachment portion are separate components.

The sealing arrangement 110 provides a fluid seal for the rotary joint. The sealing arrangement 110 may be configured in a variety of ways. Any suitable configuration may be used, including various seal numbers, seal types, seal locations, and seal orientations. In the illustrated embodiment, a first seal 192 and a second seal 194 are positioned in the cylindrical inner side surface 186 of the first end 152 of the second conduit 106. The cylindrical inner side surface 186 includes a first annular groove 196 for receiving the first seal 192 and a second annular groove 198 for receiving the second seal 194. The first and

second seals

192, 194 rotate with the second conduit 106 when the first and

second seals

192, 194 are installed in the first and second

annular grooves

196, 198, respectively. However, in other embodiments, the sealing arrangement 110 may include more or less than two seals, and the seals may be mounted such that the seals do not rotate with the second conduit 106 (e.g., mounted in an annular groove located in the first conduit 104).

In the illustrated embodiment, the first and

second seals

192, 194 may be any suitable type of seal, including energized seals (double or non-double acting) and/or non-energized seals. Suitable seals include, but are not limited to, energized or non-energized radial face seals, lip-type or double-lip-type seals, rubber static seals (e.g., O-rings, D-rings, elastomeric substances), non-energized rubber seals, energized rotating lip seals, rotating deposited PTFE seals, metal face seals, packing/gland seals, energized or non-energized PTFE seals, low speed reciprocating seals, and finger spring energized PTFE seals. The first seal 192 and the second seal 194 may be substantially identical. However, in other embodiments, the first seal 192 may be a different type of seal, or may be arranged in a different orientation than the second seal 194. In another exemplary embodiment, the first seal 192 and/or the second seal 194 may be a radial lip seal. Any suitable radial lip seal may be used. For example, conventional radial lip seals are generally U-shaped and form an annular channel. In embodiments utilizing one or more radial lip seals, the one or more lip seals are arranged such that the channel of the lip seal faces downstream (i.e., toward the second end of the second conduit 106) such that any debris to which the lip seal is exposed will fall away from the channel by gravity and not collect in the channel.

Because the first and

second seals

192, 194 are positioned in the cylindrical inner side surface 186 of the first end 152 of the second conduit 106, when the first conduit 104 is received in the first end 152 of the second conduit 106, fluid exits the second end 172 of the first conduit 104 downstream of the first and

second seals

192, 194.

Referring to fig. 2 and 4, in the illustrated embodiment, the mounting portion 118 is below the gear train portion 114 (i.e., downstream along the longitudinal axis B) to at least partially isolate the gear train portion 114 from shear and bending forces transmitted to the transmission housing 112 via the mounting portion 118 during operation of the rotary drill rig. The mounting portion 118 may be constructed in various ways. In the illustrated embodiment, the mounting portion 118 includes a proximal end 188 and a distal end 190 opposite the proximal end 188.

In the illustrated embodiment, the mounting portion 118 includes two spaced apart rectangular second mounting surfaces 124 and two spaced apart rectangular first mounting surfaces 122 that are substantially similar to the second mounting surfaces 124, but are positioned on an opposite side of the mounting portion 118 from the first mounting surfaces 122. However, in other embodiments, the mounting portion 118 may include more or less than two first mounting surfaces 122 and/or more or less than two second mounting surfaces.

In the illustrated embodiment, the two spaced apart first mounting surfaces 122 are coplanar and the two spaced apart second mounting surfaces 124 are coplanar. However, in other embodiments, the two spaced apart first mounting surfaces 122 may not be coplanar and the two spaced apart second mounting surfaces 124 may not be coplanar.

In the illustrated embodiment, the first and second mounting surfaces 122, 124 are radially outward of and collinear with the second and

third roller bearings

162, 164. Each of the first and second mounting surfaces 122, 124 includes a plurality of mounting holes 200 for receiving bolts to attach the rotary gearbox 100 to the

guides

102, 103. Thus, the rotary transmission has a first side bolted joint and a second side bolted joint. The number and arrangement of mounting holes 200 may vary for different embodiments.

The first and second mounting surfaces 122, 124 include structures that improve the shear strength of the side bolted joint and prevent relative rotation between the rotary gearbox 100 and the

guides

102, 103. The structure that improves shear strength and prevents rotation may be constructed in a variety of ways. In the illustrated embodiment, the first mounting surface 122 includes a first keyway 202 extending across both first mounting surfaces 122. In addition, the second mounting surface 124 includes a second keyway 204 that extends across both second mounting surfaces 124. In the illustrated embodiment, each of the first and

second keyways

202, 204 is formed as a linear groove extending horizontally and coaxially (i.e., perpendicular to the longitudinal axis B) across the two first mounting surfaces 122 and across the two second mounting surfaces 124, respectively. However, in other embodiments, the first keyway 202 and the second keyway 204 may extend other than horizontally, e.g., as extending at any angle that is not perpendicular, such as transverse to the longitudinal axis B. In the illustrated embodiment, one or more of the mounting holes 200 are located within the

keyways

202, 204.

In the illustrated embodiment, each of the one or more first spacers 120 is configured to be bolted between one of the first mounting surfaces 122 and one of the first guides 102. Similarly, each of the one or more second spacers 123 is configured to be bolted between one of the second mounting surfaces 124 and one of the second guides 103.

In the illustrated embodiment, four

spacers

120, 123 are used to connect the transmission housing 112 to the

guides

102, 103. Specifically, a first spacer 120 is connected to one of the first mounting surfaces 122, and another first spacer 120 is connected to the other of the two first mounting surfaces 122. Similarly, a second spacer 123 is connected to one of the second mounting surfaces 124, and another second spacer 123 is connected to the other of the two second mounting surfaces 124. In other embodiments, the number of first mounting surfaces 122, the number of second mounting surfaces 124, and the number of

spacers

120, 123 may vary in different embodiments. For example, in some embodiments, the

guides

102, 103 may be attached to the mounting portion 118 without the use of the

spacers

120, 123. Further, in some embodiments, a single spacer may be attached to multiple mounting surfaces, or multiple spacers may be attached to a single mounting surface. Any suitable number of spacers and mounting surfaces may be used to connect the transmission housing 112 to the

guides

102, 103.

In the illustrated embodiment, the one or more first spacers 120 are identical to the one or more second spacers 123, and the first and

second spacers

120, 123 are used interchangeably. Thus, in fig. 4, the spacer is referred to and described as a first spacer 120. However, in other embodiments, the first and

second spacers

120, 123 may be different, and the first and second mounting surfaces 122, 124 may be configured differently.

Referring to fig. 4, the first spacer 120 includes a first mating surface 210 configured to engage the first mounting surface 122 or the second mounting surface 124 of the mounting portion 118. The first mating surface 210 may be shaped similar to the first mounting surface 122, e.g., like a rectangular shape similar to or the same as the first mounting surface 122. The first mating surface 210 includes a key 212 configured to be received in the keyway 202 of one of the first mounting surfaces 122 or in the keyway 204 of one of the second mounting surfaces 122. In the illustrated embodiment, the key 212 is formed as a horizontal ridge that is complementary to the

horizontal groove keyways

202, 204. In an exemplary embodiment, the key 212 is configured to be received within one of the

keyways

202, 204 via a press fit. The key 212 and

keyways

202, 204 may be any suitable shape, size, or orientation that allows the key/keyway combination to improve the shear strength of the side bolted joint and prevent relative rotation between the rotary gearbox 100 and the

guides

102, 103. In other embodiments, the first mating surface 210 may include a keyway configured to receive a key of one of the first mounting surfaces 122 or one of the second mounting surfaces 122.

The first spacer 120 includes a second mating surface 214 configured to mount to one or more of the

guides

102, 103. The second mating surface 214 is opposite the first mating surface 210. The second mating surface 214 may be configured to mount to one or more of the

guides

102, 103 in any suitable manner. In the illustrated embodiment, the second mating surface 214 has a similar rectangular shape as the first mating surface 210. The first mating surface 210 has a key 212 and the second mating surface 214 has a keyway 216. The keyway 216 is configured to receive a guide key 218 associated with the

guide

102, 103. The guide key 218 may be constructed in various ways. Any configuration that may be received within the keyway 216 to improve the shear strength of the side bolted joint and prevent relative rotation between the rotary gearbox 100 and the

guides

102, 103 may be used.

In the illustrated embodiment, the guide key 218 is a generally rectangular or oblong bar or protrusion sized to be received in the keyway 216 and to span the length of the keyway 216 on the first spacer 120. In an exemplary embodiment, the guide key 218 is configured to be received within the keyway 216 via a press fit. The guide key slot 216 may be a separate component or integrally formed with the

guide members

102, 103 or another component. In other embodiments, the second mating surface 214 may comprise a key configured to be received in a keyway of the

guide key

102, 103 or a component associated with the guide.

The first and

second spacers

120, 123 include a plurality of through-holes 220 extending through the first spacer 120 from the first mating surface 210 to the second mating surface 214. In the illustrated embodiment, at least one through hole 220 extends from the keyway 216 through the first spacer 120 and through the key 212. The through-hole 220 is arranged to align with the mounting hole 200 in the first or second mounting

surface

122, 124 such that a bolt (not shown) extending through the through-hole will engage with the mounting hole 200 in the gearbox housing 112.

Referring to fig. 5-6, the top plate 136 includes a top surface 221, a bottom surface 222 generally parallel to and opposite the top surface 221, and a plurality of side surfaces 224 extending between the top surface 221 and the bottom surface 222. In the illustrated embodiment, the top plate 136 is generally rectangular with four side surfaces 224. However, in other embodiments, the top plate 136 may be configured in any suitable shape having more or less than four side surfaces 224.

The bottom surface 222 includes one or more protrusions 226 that align or position the top plate 136 with the top end 130 of the rotary transmission housing 112 and improve the shear strength of the top bolted joint (i.e., where the top plate 136 is bolted to the top end 130) and aid in the alignment of the gear train 116 with the rotary joint. The one or more protrusions 226 may be configured in a variety of ways. Any suitable shape, size, location and number of protrusions may be used. In the illustrated embodiment, the bottom surface 222 includes one of the one or more protrusions 226 adjacent to a corner 228 between two of the side surfaces 224. In one exemplary embodiment, the bottom surface 222 includes protrusions 226 at two opposing corners between the side surfaces 224.

In the illustrated embodiment, the protrusion 226 includes a first engagement surface 230 that extends parallel to one of the side surfaces 224, and a second engagement surface 232 that extends parallel to the other of the side surfaces 224 and is generally perpendicular to the first engagement surface 230.

Referring to FIG. 6, the transmission housing 112 includes one or more recesses 236 adjacent the top end 130 of the gear train portion 114. Each of the one or more recesses 236 is configured to receive and cooperate with a corresponding one of the protrusions 226. The one or more recesses 236 may be configured in a variety of ways. Any suitable shape, size, location, and number of protrusions that may cooperate with the protrusions 226 to align or position the top plate 136 with the top end 130 of the rotary transmission housing 112 and improve the shear strength of the top bolted joint may be used.

In the illustrated embodiment, one of the one or more recesses 236 is provided corresponding to each of the protrusions 226. The recess 236 includes a first shoulder 240 extending parallel to and engaging the first engagement surface 230 and a second shoulder 242 extending parallel to and engaging the second engagement surface 232.

INDUSTRIAL APPLICABILITY

The present disclosure is applicable to systems having a rotary joint, and particularly relates to a rotary gearbox for a rotary drill rig. In an exemplary embodiment of the disclosed rotary gearbox 100, the rotary gearbox 100 includes features that extend the life of the sealing arrangement for the rotary joint. In the exemplary embodiment, rotary gearbox 100 includes a guide feature relative to the rotary joint, wherein an outlet of first conduit 104 is received within an inlet of second conduit 106. As a result, the flow exiting the first conduit 104 enters the second conduit 106 downstream of the seal arrangement 110. Thus, the dynamic pressure of the fluid flowing through the

conduits

104, 106 does not force the fluid, and any debris in the fluid that may reduce the life of the sealing arrangement, into the sealing arrangement.

In an exemplary embodiment, the sealing arrangement 110 may include a plurality of

annular seals

192, 194 arranged in series and mounted to rotate with the second conduit 106 during operation. Having more than one annular seal provides an additional layer of sealing to extend the life of the sealing arrangement 110.

In an exemplary embodiment, the rotary gearbox 100 includes features that improve the load capacity of the rotary gearbox 100 and reduce deflection of the geartrain portion 114 during pull-up and pull-down operations of the rotary drill. In an exemplary embodiment, the transmission housing 112 is mounted to the

guides

102, 103 in a position where pull-up and pull-down forces during operation do not cause excessive deflection of the transmission housing 112, which may cause damage to the gears and bearings due to misalignment of the gear train.

For example, in the illustrated embodiment, all or at least a majority of the mounting portion 118 is spaced away from the gear train portion 114. Thus, the pull-up and pull-down forces are at least partially isolated from the gear train portion 114 of the transmission housing 112 and deflection of the gear train portion 114 is reduced.

In the exemplary embodiment, rotary transmission 100 also includes a three roller bearing design. The first roller bearing 160 is positioned at the first end 152 of the second conduit 106 and supports the second end. In the illustrated embodiment, the second and

third roller bearings

162, 164 are positioned in the mounting portion 118 (i.e., spaced apart from the gear train portion 114) such that the first and second mounting surfaces 122, 124 are radially aligned with the second and

third roller bearings

162, 164. Thus, the strain caused by the pull-up and pull-down forces is transmitted directly through the mounting portion 118 and the second and

third roller bearings

162, 164 without significantly affecting the gear train 116.

The second roller bearing 162 is positioned toward the middle of the transmission housing 112 and tapers outward to absorb a greater amount of the pull down force of the drill than the other bearings. Since the pull-down force of the drill rig is greater than the pull-up force and is typically applied for a longer duration than the pull-up force, it is advantageous to position the second roller bearing 162 at or near the longitudinal middle of the gearbox housing 112 (where more of the housing structure surrounds and supports the second roller bearing 162).

A third roller bearing 164 is positioned at or toward the second end 154 of the second conduit and tapers inwardly in the direction of flow through the passage 156. Thus, because the second and

third roller bearings

162, 164 are positioned below the gear train portion 114, the shear forces transmitted through the second and

third roller bearings

162, 164 are at least partially isolated from the gear train portion 114.

In an exemplary embodiment, the side bolted joints that attach the transmission housing 112 to the

guides

102, 103 include key and keyway (or groove and ridge) features that improve the shear strength of the bolted joints and also prevent relative rotation between the transmission housing 112 and the

guides

102, 103. In one exemplary embodiment, the side bolt joints include spacers that incorporate keys and keyways with the transmission housing 112.

In the exemplary embodiment, the protrusion 226 and the recess 236 define a guide feature that positions the top plate 136 relative to the top end 130 of the transmission housing 112. The interaction between the protrusion 226 and the recess 236 also improves the shear strength of the top bolted joint and facilitates alignment of the gear train 116 and the swivel joint.

It should be appreciated that the foregoing description provides examples of the disclosed system. However, it is contemplated that other embodiments of the present disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that time and are not intended to more generally imply any limitation as to the scope of the disclosure. All differences and unfavorable statements concerning certain features are intended to imply that these features are not preferred, but not exclusive of all features from the scope of the invention unless otherwise indicated.

The use of the terms "a" and "an" and "the" and "at least one" and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Use of the term "at least one" followed by a list of one or more items (e.g., "at least one of a and B") should be interpreted to mean one item selected from the list of items (a or B) or any combination of two or more of the list of items (a and B), unless the context clearly dictates otherwise or is clearly contradicted by context.

Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. In addition, this disclosure covers any combination of the above-described elements in all possible variations thereof unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims

1. A rotary gearbox for a rotary drill, the rotary gearbox configured to be mounted to a guide of the rotary drill, the rotary gearbox comprising:

a plurality of gears; and

a transmission housing, the transmission housing comprising:

A gear train portion accommodating the plurality of gears; and

a mounting portion defining a mounting surface for mounting the transmission housing to the guide,

wherein at least a majority of the mounting surface is spaced from the gear train portion relative to a longitudinal axis of the rotary transmission case.

2. The rotary transmission of claim 1, wherein the mounting surface comprises a keyway extending in a direction transverse to the longitudinal axis.

3. The rotary transmission of claim 2, wherein a spacer extends between the mounting surface and the guide, and the spacer includes a key configured to be received within the keyway.

4. The rotary gearbox of claim 2, further comprising a second mounting surface spaced apart from and coplanar with the mounting surface, and wherein the keyway extends across both the mounting surface and the second mounting surface.

5. The rotary gearbox of any one of claims 1-4, further comprising:

a first conduit fixedly attached relative to the transmission housing and having a first end defining an outlet;

a second conduit extending at least partially through the transmission housing, the second conduit having a second end defining an inlet, the second conduit being rotatable relative to the first conduit and the transmission housing and arranged coaxially with the first conduit, wherein the first end of the first conduit is received within the second end of the second conduit; and

A sealing arrangement positioned radially between a first end of the first conduit and a second end of the second conduit,

wherein the outlet of the first conduit is downstream of the sealing arrangement.

6. The rotary gearbox of claim 5, wherein the sealing arrangement is mounted for rotation with the second conduit.

7. The rotary gearbox of claim 5 or 6, wherein the sealing arrangement comprises a plurality of annular seals arranged in series.

8. The rotary gearbox of any one of claims 5-7, further comprising:

a first roller bearing mounted within the transmission housing adjacent the second end of the second conduit;

a second roller bearing mounted within the transmission housing adjacent a distal end of the mounting portion; and

a third roller bearing mounted within the gearbox housing between the first roller bearing and the second roller bearing.

9. The rotary transmission of claim 8, wherein the first roller bearing is mounted within a gear train portion of the transmission housing, and the second and third roller bearings are mounted within a mounting portion of the transmission housing.

10. The rotary gearbox of claim 8 or 9, wherein the second roller bearing is configured as a pull-up bearing and the third roller bearing is configured as a pull-down bearing.